1. Field of the Invention
The present invention relates to an apparatus and method for making or processing a fiber suspension used in a paper-making machine, and, more particularly, to an apparatus providing process water used for making or processing the fiber suspension.
2. Description of the Related Art
A paper-making machine typically receives a fiber suspension, such as a wood fiber suspension, at the wet end thereof. The fiber suspension is discharged with a known cross-sectional profile across the width of the machine onto a forming fabric. The fiber suspension is drained, pressed and dried to ultimately form a paper web as an end product. Typically, the fiber suspension is treated in a plurality of steps known as "stock preparation" so that a fiber suspension with known physical properties may be supplied to the wet end of the machine. One such treating process involves the use of a "pulp washer" which washes the fiber suspension using a plurality of showers which extend across the width of the fiber suspension. The showers utilize one or more different grades of process water and fresh water. The process water may be segregated into different grades having different respective contamination levels. Different grades of process water may be suitably used for different parts of the pulp washing operation. Since a pulp washer utilizes the plurality of showers at different locations therein to effect the pulp washing process, it is of course necessary to ensure that an adequate supply of process water is available.
What is needed in the art is an apparatus for supplying an adequate amount of process water with a contamination level at or below a predetermined level.